1. Field of the Invention
The present invention is related to a sport boot including an external sole on which an upper equipped with an opening to enable passage of the foot is mounted. The boot includes an internal quarter and an external quarter connected to one another by a closure system constituted by a lace or cable forming two strands, in connection with a blocking device or blocker and mutually connecting a series of return elements along a determined alternate path, fixedly arranged on the quarters on either side of the opening in the vicinity of their respective edges located across from each other and defining a lacing zone, so that during a traction on the strands of the lace or cable, the latter tightens along the quarters by means of return elements to bring the quarters close together and to maintain them in tightening position on the foot by means of the blocker.
2. Discussion of Background and Material Information
A similar boot is known from U.S. Pat. No. 262,653 which discloses a lacing device using only one lace, whose single strand is alternately passed behind the return elements located on either side and in an offset manner on each quarter of the boot. According to this device, the single strand of the lace is hooked by one of its ends in a lower end zone of the lacing located towards the front of the boot, whereas, at its other end directed towards the upper portion of the boot, it comprises a hooking device for the free end of said strand after tightening.
Such a lacing device clearly shows that the tightening produced by a single strand has the major disadvantage of providing a poor distribution of the tension exerted on the lace.
According to another document constituted by Italian Patent No. 19700/83, a lacing device constituted by a lace forming two strands is also known, whose ends, located in the lower lacing zone, mutually form a non-discontinuous loop adapted to freely slide into the last return elements located in this zone, in accordance with the traction exerted on each strand during tightening. The blocking of the lace after tightening is obtained by a blocker arranged at the other end of the strands.
According to a first embodiment of this device, the tightening of the lace is obtained by a traction on the end of the free strands, after which, the blocker, inserted between said strands, is slidably brought into blocking position.
In this way, since traction inequalities are inevitably produced on each strand during tightening of the boot, it results in a progressive dislocation of the placement of the blocker with respect to the median lacing line, this dislocation can go as far as to release one of the strands. In addition to the poor tightening and tension distribution thus caused, another disadvantage resides at the manufacturing level. Indeed, during assembly, it is difficult to precisely center the blocker placement.
According to a second embodiment, partially overcoming the disadvantages of the first, the free ends of the lace strands are joined with respect to one another in the form of a loop, and the blocker is arranged between the strands, but in the lacing zone, i.e., between two pairs of successive return elements. Such an arrangement not only hampers the action on the blocker when the lacing zone is finally covered, which further leads to the implementation of a supplementary activating cable of said blocker, rendering a blind activation of the latter from an external zone of the boot, but in addition, as soon as the cable can freely slide in the end lacing zone, the disadvantage mentioned above in the first embodiment remains, namely, a poor tightening and distribution of the tension on each strand.